Gases may form in an engine crankcase when gases from engine cylinders bypass engine pistons and enter the crankcase during engine rotation. These gases are commonly referred to as blow-by gasses. The blow-by gases can be combusted within engine cylinders to reduce engine hydrocarbon emissions via returning the crankcase gases to the engine air intake and combusting the gases with a fresh air-fuel mixture. Combusting crankcase gases via the engine cylinders may require a motive force to move the crankcase gases from the engine crankcase to the engine air intake. One way to provide motive force to move crankcase gases to engine cylinders is to provide pneumatic communication between an engine outlet port receiving engine crankcase gases and a low pressure region (e.g., vacuum) of the engine intake manifold downstream of an engine throttle body. Specifically, external lines or conduits are coupled to the engine outlet port, thereby directing crankcase gases to the engine air intake system. Thus, the gases ventilated from the crankcase are externally routed from the engine crankcase to the engine intake system. In this way, engine vacuum can draw crankcase gases into the engine cylinders for combustion.
However, external routing the positive crankcase ventilation (PCV) lines increases the profile of the engine which may increase vehicle height, thereby reducing vehicle fuel economy. Moreover, it may be possible for externally routed PCV lines to become degraded or removed by a vehicle operator, thereby increasing vehicle emissions.
As such, the inventors herein have recognized the above-mentioned disadvantages and have developed a PCV system. The PCV system includes an engine assembly, the engine assembly including an engine block, a cylinder head, a valve cover, and an intake manifold and a PCV passage providing fluidic communication between a crankcase of the engine assembly and a cylinder intake port of the engine assembly without hoses or conduits external to the engine assembly. By integrating the PCV lines into the cylinder head the compactness of the engine is increased. Furthermore, PCV line degradation may be reduced because the lines are not exposed to the operator or environment.
The present description may provide several advantages. In particular, the approach may provide increased functionality so as to better utilize engine structure via increased PCV oil return passage functionality. In addition, the approach may reduce engine emissions by retaining PCV gases within the engine structure and reducing the possibility of PCV line degradation. Further, the PCV passages may not be as easily removed allowing crankcase gases to escape to ambient surroundings.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.